The present invention relates to an improved electrostatic recording multi-stylus electrode device for use with a facsimile apparatus or the like.
Conventionally, an electrostatic recording multi-stylus electrode device, as shown in FIGS. 1 to 4, is known for use with a facsimile apparatus or the like, in which a recording electrode comprising multiple stylus electrodes is arranged so as to face an auxiliary electrode (not shown) with a small gap therebetween, a recording medium comprising an insulating layer is placed between the recording electrode the auxiliary electrode, and voltage correlated to informatin information be recorded is applied across the recording electrode and the auxiliary electrode, and the recording medium is scanned by both electrodes so that a latent electrostatic image is formed on the recording medium, and, by developing the latent image, the information is recorded on the recording medium.
Referring to FIG. 1, multiple stylus electrodes P are embedded in a row in a rod-shaped electrode support member 1 made of a resin. The stylus electrodes P have to be embedded very closely in the row so that the stylus electrodes P can attain a high scanning density. However, in FIG. 1, the stylus electrodes P are illustrated with a large space therebetween for a better understanding of the arrangement of the respective multiple stylus electrodes.
The stylus electrodes are embedded in the form of an electrode row a--a and, as a whole, constitute a recording electrode and are respectively connected to lead wires e.sub.1, e.sub.2, e.sub.3, . . . , e.sub.n, which are extended from "m" common connecting conductive members, for example, common connecting conductive members q.sub.1, q.sub.2, q.sub.3 and q.sub.4. These common connecting conductive members are arranged parallel to each other in an insulating base plate 2.
More specifically, the respective lead wires extended from the common connecting conductive members are connected to the stylus electrodes P spaced apart by (m-1) stylus electrodes, for example, spaced apart by three stylus electrodes in FIGS. 1 to 4.
One end of each common connecting conductive member, such as q.sub.1, q.sub.2, q.sub.3, q.sub.4, is connected to a connector (not shown). When a latent electrostatic image is formed, an insulating recording medium is fed between the recording electrode and the auxiliary electrode (not shown) which is disposed in close proximity to the recording electrode, so that a potential correlated to information to be recorded is applied across the electrodes through each connector to scan the insulating recording medium.
Practically, the insulating base plate 2 and the electrode support member 1 are made integrally of a resin, such as epoxy resin, as shown in FIG. 2, so that one multi-stylus electrode device 3 is constructed as a whole. In FIG. 1, however, for a better understanding of the multi-stylus electrode device 3, each part is fragmentarily illustrated.
FIG. 3 shows the wiring of the multi-stylus electrode device 3.
In the conventional multi-stylus electrode of this type, a floating electrostatic capacity of capacitors formed between the lead wires e.sub.1, e.sub.2, e.sub.3, e.sub.4, . . . , e.sub.n, and between the common connecting conductive members q.sub.1, q.sub.2, q.sub.3, q.sub.4 becomes a problem when a potential is applied to the multi-stylus electrode device 3 for the formation of a latent electrostatic image. The term "floating electrostatic capacity" as used herein refers to the electrostatic capacity of the capacitors formed by the respective lead wires and the respective common connecting conductive members. Particularly, the floating electrostatic capacity of each capacitor formed between the lead wires e.sub.1, e.sub.2, e.sub.3, . . . , e.sub.n, differs significantly since the length of each lead wire is different. This gives rise to an uneven image density. In this type of multi-stylus electrode device, the thus caused uneven image density is an important problem to be solved.
Conventionally, in order to solve this problem, a wiring method as shown in FIG. 4 has been proposed. In this method, the respective common connecting conductive members q.sub.1, q.sub.2, q.sub.3, q.sub.4 are disposed oppositely in the central portion of the electrode row a--a so that the relative length differences between the lead wires e.sub.1, e.sub.2, e.sub.3, e.sub.4, . . . , e.sub.n which are extended from the common connecting conductive members and then connected to the stylus electrodes are made substantially equal in order to minimize the uneven distribution of the floating capacity in the recording electrode portion, for instance, in the respective connectors. However, this method cannot make the distribution of the floating electrostatic capacity completely uniform. Moreover, since the common connecting conductive members have to be disposed oppositely in the central portion of the insulating plate, the wiring is difficult and wrong wirings are apt to occur. In short, this method does not provide a perfect solution to the above-mentioned problem.